首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12882篇
  免费   692篇
  国内免费   75篇
耳鼻咽喉   228篇
儿科学   261篇
妇产科学   104篇
基础医学   1765篇
口腔科学   297篇
临床医学   806篇
内科学   3480篇
皮肤病学   252篇
神经病学   884篇
特种医学   430篇
外科学   1969篇
综合类   36篇
一般理论   1篇
预防医学   332篇
眼科学   384篇
药学   976篇
中国医学   14篇
肿瘤学   1430篇
  2023年   75篇
  2022年   103篇
  2021年   241篇
  2020年   137篇
  2019年   173篇
  2018年   223篇
  2017年   160篇
  2016年   244篇
  2015年   254篇
  2014年   340篇
  2013年   365篇
  2012年   602篇
  2011年   613篇
  2010年   427篇
  2009年   335篇
  2008年   697篇
  2007年   676篇
  2006年   691篇
  2005年   772篇
  2004年   765篇
  2003年   747篇
  2002年   735篇
  2001年   373篇
  2000年   356篇
  1999年   318篇
  1998年   176篇
  1997年   149篇
  1996年   147篇
  1995年   121篇
  1994年   91篇
  1993年   94篇
  1992年   222篇
  1991年   195篇
  1990年   200篇
  1989年   194篇
  1988年   172篇
  1987年   159篇
  1986年   141篇
  1985年   126篇
  1984年   115篇
  1983年   78篇
  1982年   54篇
  1981年   52篇
  1979年   79篇
  1978年   68篇
  1976年   50篇
  1974年   48篇
  1972年   49篇
  1970年   44篇
  1968年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
We report a case of a diaphragmatic hernia after a heart transplant operation. A 43-year-old woman, who underwent orthotropic heart transplantation for hypertrophic cadiomyopathy two year earlier, presented with vomiting and epigastric pain. A computed tomography scan showed that the stomach and transverse colon were dislocated in the left thoracic cavity. We diagnosed left diaphragmatic hernia incarceration and performed laparoscopic repair of the diaphragmatic hernia. A 12 × 8 cm diaphragmatic defect was found intraoperatively on the ventrolateral aspect of the left diaphragm, and the stomach with volvulus had herniated into the thorax through the defect. The hernia was considered to be iatrogenic. The diaphragmatic defect was large, and the diaphragm was thinning. We closed the defect by mesh repair. Laparoscopic mesh repair of the diaphragmatic hernia could be performed safely and with minimal invasiveness.  相似文献   
4.
5.
6.
7.
BACKGROUND: The therapies for refractory ulcers on the oral mucosa are symptomatic and very unsatisfactory. We hypothesized that application of growth factors might be able to achieve successful remission of the lesion. We evaluated the effects of systemic administration and topical application of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on impaired wound healing of ulcers in the rabbit gingiva. METHODS: Almost uniform round ulcers could be created on the gingiva of the rabbits by chemical injury with acetic acid. When the submandibular glands were removed or i.v. injection of cisplatin (CDDP) and peplomycin sulfate was performed before ulcer formation, healing of the ulcers took longer than in untreated rabbits. To ascertain whether or not human EGF and bFGF affect rabbit cells, we first examined the effects of EGF and bFGF on the proliferation of the cells derived from rabbit gingiva. We then applied EGF or bFGF in these impaired healing models. RESULTS: EGF and bFGF promoted proliferation of the fibroblasts, and EGF also promoted proliferation of the keratinocytes isolated from gingival tissue of rabbits in vitro. Systemic injections of EGF and bFGF in rabbits, which had their submandibular glands removed, and topical application of bFGF accelerated healing of ulcers created in rabbits injected with CDDP and peplomycin sulfate. The ability of bFGF to promote the healing of ulcers was much greater than that of EGF. CONCLUSION: Basic FGF may be effective for refractory oral mucosal lesions.  相似文献   
8.
9.
We examined the mechanisms of the inhibition of DNA synthesis by a new platinum compound, (-)-( R )-2-aminomethylpyrrolidine(1,1-cyclobutane-dicarboxylato)-2-platinum(II) monohydrate (DWA-2114R), a derivative of the antitumor drug cis- diamminedichloroplatinum(II) (CDDP), using prokaryotic and eukaryotic DNA polymerases. Preincubating activated DNA with CDDP or DWA-2114R reduced its template activity for prokaryotic and eukaryotic DNA polymerases in a dose-dependent manner. DWA2114R required six times greater drug concentration and two times longer incubation time to show the same decrease of the template activity compared to CDDP. Treatment of primed pUC118 ssDNA templates with the two drugs followed by second-strand synthesis by prokaryotic and eukaryotic DNA polymerases revealed that DWA2114R bound to DNA in a similar manner to CDDP and these adducts blocked DNA elongation by DNA polymerases of eukaryotes as well as of prokaryotes. With these two drugs, the elongations by E. coli DNA polymerase I (Klenow fragment), T7 DNA polymerase and calf thymus DNA polymerase α were strongly arrested at guanine-guanine sequences (GG). Stop bands were also observed at adenine-guanine sequences (AG) guanine-adenine-guanine sequences (GAG) and mono-guanine sequence (G). Calf testis DNA polymerase β was also arrested efficiently at AG, GAG and G, but much more weakly at GG. This pattern was common to DWA2114R and CDDP.  相似文献   
10.
Effects of N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide (DM-9384) on learning and memory were studied using four different experimental rat models. In electroconvulsive shock- or scopolamine-induced amnesia in the step-through passive avoidance task, DM-9384 improved both types of amnesia when administered before the training trial. Aniracetam also showed similar but somewhat weaker effects. Furthermore, in the scopolamine amnesia model, an improvement was confirmed with arecoline. The dose-response curves for these compounds were bell-shaped. In the shuttle box active avoidance task, DM-9384 administered daily 1 hr before each training session facilitated the acquisition process of the avoidance response. In addition, the experiment of light-dark discrimination task with positive reinforcement showed that this compound administered daily after each session slightly accelerated the acquisition process of the correct response. These results suggest an ability of DM-9384 to enhance cognitive functions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号